At present, a luminal stent graft may be adopted to implement endovascular graft exclusion to isolate a diseased region in a human body lumen, for example, the luminal stent graft may be adopted to isolate an artery dissection or an arterial aneurysm in a blood vessel. This kind of method has gradually substituted traditional invasive operation due to its advantages of a small operation wound, small intraoperative blood transfusion volume, quick postoperative recovery, short hospital stay, and the like. The luminal stent generally has radial expandability, and is clung to a vascular cavity wall by using its radial supporting force so as to be fixed in a lumen. To prevent the stent graft from falling off, the stent graft needs to have a high enough radial supporting force, but the higher radial supporting force indicates higher rigidity of the radially unfolded stent. However, due to individual differences, the inner walls of lumens are of different shapes, and also may have calcified plaques that would change their shapes; and the luminal stent graft with relatively high rigidity may possibly result in a poor or decreased ability to cling to a luminal wall, so that a space between the stent graft and a diseased luminal wall may not be completely closed.
For example, with reference to FIG. 1, a plaque 13 on the inner wall of a lumen 12 may form a clearance 14 between a stent graft 11 and the inner wall of the lumen 12, and blood flow may flow to a tumor cavity or a dissection false cavity through the clearance 14, thus generating type-I endoleak. Alternatively, to open up main body blood vessels and branch blood vessels at the same time, multiple stent grafts are used cooperatively by adopting a chimney technology, a periscope technology or a sandwich technology, and then are respectively implanted into the main body blood vessels and the branch blood vessels. For example, with reference to FIG. 2, one end of a main body stent graft 15 and one end of a branch stent graft 16 are abreast implanted into the lumen 12, and the other end of the main body stent graft 15 is communicated with a relatively large main body blood vessel (not shown in the figure), but the other end of the branch stent graft 16 is communicated with a relatively small branch blood vessel (not shown in the figure). To make sure that the blood flow flowing into the branch blood vessel is unblocked, the radial supporting force of the branch stent graft 16 needs to be greater than that of the main body stent graft 15, and this would lead to a situation that portions, which are located at the abreast implanted positions, of the main body stent graft 15 are easier to deform radially to form a clearance 17 among the branch stent graft 16, the main body stent graft 15 and the inner wall of the lumen 12, thus generating the type-I endoleak, and the blood flow may flow to the tumor cavity or the dissection false cavity through the clearance 17.
This type-I endoleak may appear in a thoracic aorta, an abdominal aorta or other lumens. Continuous inflow of the blood flow may cause continuous enlargement of the dissection false cavity or an arterial aneurysm cavity, and finally result in a serious consequence of breakage of the dissection false cavity or the arterial aneurysm cavity, so that the endovascular graft exclusion may fail. Therefore, to enhance the surgical effect and increase the healing success rate, it is very important for the luminal stent graft used in the endovascular graft exclusion to avoid the type-I endoleak between the stent graft and the lumen as much as possible.